The present invention relates to game balls used in diamond sports. More particularly, the present invention is concerned with game balls, such as softballs, having a dual core construction that is suitable for play under competitive play conditions.
Specifications for softballs used in competitive and tournament play have generally been issued by two governing organizations, the United States Specialty Sports Association (USSSA) and the American Softball Association (ASA). Softballs range in size from 10 to 16 inches in circumference, with 12-inch softballs being the most widely used. The specifications for a 12-inch softball include the following requirements: Coefficient of Restitution (COR) of 0.40 to 0.50; circumference of 11⅞ to 12⅛ inches; compression limits of 375 or 525 pounds, depending on the organization; and weight of 6¼ to 7 ounces (175 to 200 grams).
The COR is extremely important because the COR generally determines the speed of the ball off the bat. More specifically, a ball's COR is the ratio of the relative velocity of the ball after and before direct impact with a fixed surface. As discussed in greater detail below, COR is measured by propelling the ball against a hard surface at 88 feet-per-second (fps) and measuring the rebound speed of the ball. COR is expressed in terms of the ratio of the rebound speed to the initial ball speed of 88 fps. Consequently, the COR can vary from zero to one, with one being equivalent to a fully elastic collision and zero being equivalent to an inelastic collision.
There are other qualities of softballs that are not included in the official specifications or physical properties that are important to players. Examples of these qualities include: the sound of the ball when batted; the “feel off the bat” or, the feel that the batter experiences at the moment of impact of the bat with the ball; flight consistency; durability; the grip and feel of the ball in both bare hands and in a glove; and the ability of the product to maintain those characteristics over an extended period of time.
The various associations that govern softball are continuously investigating the merits of lower compression softballs and how they could benefit the game of softball. Urethane and cork centered softballs have to comply with softball association compression limits that are currently set at either 525 lbs. or 375 lbs., depending on the league and level of play. A softball's compression is obtained by measuring the amount of force required to compress the ball 0.25 inches as prescribed by ASTM methodology (ASTM method F 1888-98). That is, compression determines the pounds of pressure per square inch required to compress a softball 0.25 inches. Compression can be measured using universal test machines that compress the ball between two flat steel platens and record the force with a load cell, such as Instron™, MTS™ or other types machines. Using typical urethane and cork softball constructions, softball manufacturers continually adjust ball constructions to meet the softball associations' compression requirements while continuing to satisfy the ball performance demands required by the players. What is needed in the art is a softball where the performance characteristics can be altered as desired such that the softball has a very low compression while maintaining the standards for COR, durability and performance.
An innovative, multi-layer softball design has been developed that can satisfy the need for lower compressions, while maintaining the performance of a traditional softball. The COR and durability of the new multi-layer product are comparable to a traditional softball at much lower compressions. This innovative new ball also minimizes bat denting and reduces the amount of sting associated with hits that miss the sweet spot of the bat.